1. Field of the Invention
The present invention relates generally to hinge mechanisms. More particularly, the present invention relates to a hinge mechanism which is suitable for use in a portable computing device.
2. Description of the Related Art
The use of personal computers is widespread, and is rapidly becoming even more prevalent. As advances in technology enable the size of personal computers to decrease, the use of portable computers such as notebook, or laptop, computers and notepad computers is increasing. The portability of notebook computers and notepad computers enables a user to keep his or her computer readily accessible such that computing resources are effectively always at hand.
Many portable computers are configured such that a display screen of the computer pivots, or rotates, with respect to the base of the computer. FIG. 1 is a diagrammatic representation of a portable computer or, more specifically, a notebook computer 102. Notebook computer 102 includes a rotating, or hinging, section 106 and a fixed section 110. Rotating section 106 typically includes a display screen 114, while fixed section 110 often includes an input/output device such as a keyboard 118. fixed section 110 also houses a central processing unit and other computer hardware not shown).
Hinges 122 are used to allow rotating section 106 to rotate with respect to fixed action 110. As shown, rotating section 106 is "open" at approximately a 90 degree angle measured with respect to fixed section 110. The configuration of hinges 122 may be such that rotating section 106 is constrained to rotation within a certain range. Alternatively, in some cases, certain physical configurations of hinges 122 may enable a large range of rotation which may extend up to approximately 360 degrees.
Enabling rotating section 106 to rotate up to approximately 360 degrees with respect to fixed section 110 provides a user with the flexibility to place rotating section 106 in a variety of different orientations with respect to fixed section 110. For example, the user may allow rotating section 106 and fixed section 110 to both lie essentially flat on a planar surface. The user may also orient rotating section 106 or, more specifically, display screen 114, to face in the opposite direction from fixed section 110. Such an orientation may be desirable when notebook computer 102 is intended for use as a presentation device.
In order for rotating section 106 to be able to rotate and to hold a desired position at a given angle of rotation, hinges 122 typically include, or are associated with, brakes. The brakes, which are typically either spring-based or gear-based, as will be described below with reference to FIGS. 2a-2c, are used to effectively "lock" hinges 122 in place. Hinges 122 are locked into place to prevent rotation when no torque, or rotational force, is applied to hinges 122 or, more generally, to either rotating section 106 or fixed section 110.
FIG. 2a is a diagrammatic representation of a conventional flat spring hinge that is used in notebook and notepad computers. Flat spring hinge 202 includes an axle 204 which is used to couple a rotating section, e.g., rotating section 106 of FIG. 1, to a fixed section, e.g., fixed section 110 of FIG. 1. Axle 204 is arranged to couple the rotating section to the fixed section and to effectively serve as the axis of rotation of the rotating section with respect to the fixed section, as will be appreciated by those skilled in the art. Flat spring hinge 202 also includes a spring 208 that is effectively a friction spring. In other words, spring 208 provides the friction necessary to hold axle 204 in place once a rotational force is removed from axle 204. The friction provided by spring 208 basically enables spring 208 to clamp axle 204. In general, the shape, or configuration, of spring 208 may vary widely.
Flat spring hinge 202 typically does not support rotation of up to 360 degrees. That is, flat spring hinge 202 does not provide for 360 degree hinging. Since axle 204 provides only a single rotational axis that is shared by both a fixed section and a rotating section, configuring the fixed section and the rotating section to support 360 degree rotation is difficult, as will be appreciated by those skilled in the art.
Further, flat spring hinge 202 requires a relatively large amount of space to accommodate axle 204 and spring 208. As a result, the housings associated with fixed and rotating sections must also be relatively large in order to accommodate flat spring hinge 202. Since minimizing the size and the weight of notebook computers and other portable computing apparatus is generally desirable to enhance their portability, having a relatively large housing is usually not desirable.
Due to relatively high stresses that are experienced by flat spring hinge 202, flat spring hinge 202 is typically fabricated from metal. Hence, since housings in a notebook computer are often formed from plastic, flat spring hinge 202 may not be directly integrated into the housings. Therefore, manufacturing processes associated with fabricating notebook computers or, more specifically, coupling flat spring hinge 202 to both a rotating section and a fixed section, may be time-consuming.
Springs used in spring hinges often take on a variety of different configurations, as mentioned above. For example, a spring hinge may be a spring coil hinge that includes a coiled spring. FIG. 2b is a diagrammatic representation of a conventional spring coil hinge that is used in notebook computers. A spring coil hinge 212 is similar to flat spring hinge 202, as described above with respect to FIG. 2a Spring coil hinge 212 includes an axle 214 which is used to couple a rotating section to fixed section, and to serve as the axis of rotation of the rotating section with respect to the fixed section. Spring coil hinge 212 also includes a coiled spring 218 which provides the friction necessary to hold axle 214 in place once a rotational force is removed from axle 214. The friction provided by coiled spring 218 enables spring 218 to clamp axle 214.
Like flat spring hinge 202 of FIG. 2a, spring coil hinge 212 also does not typically support rotation of up to 360 degrees, due at least in part to the fact that axle 214 provides only a single rotational axis that is shared by both a fixed section and a rotating section. In addition, the space requirements of spring coil hinge 212 are comparable to those of flat spring hinge 202 of FIG. 2a. In other words, a relatively large amount of space to accommodate axle 214 and spring 218. Hence, the housings associated with fixed and rotating sections must also be relatively large in order to accommodate spring coil hinge 212.
In some portable computing apparatus, hinges which include deformable gears are used to allow a rotating section of the computing apparatus to rotate up to approximately 360 degrees with respect to a fixed section of the computing apparatus. FIG. 2c is a diagrammatic partial-view representation of a elastomeric gear mechanism that is used as part of a hinge for a portable computing apparatus. A first elastomeric gear 224, which may be axially coupled to a rotating section of a computing apparatus, includes teeth 226 that are effectively arranged to engage teeth 230 on a second elastomeric gear 228 that may be axially coupled to a fixed section of a computing apparatus. In general, one of first elastomeric gear 224 and second elastomeric gear 228 is fixed, e.g., second elastomeric gear 228 may be fixed while first elastomeric gear 224 rotates around second elastomeric gear 228. When a rotational force is applied to cause a rotating section to rotate with respect to a fixed section, teeth 226 engage teeth 230 to rotate first elastomeric gear 224 with respect to second elastomeric gear 228.
Once a rotational force is removed, the elastomeric properties of first elastomeric gear 224 and second elastomeric gear 228 cause them to deform against each other. As a result, friction is effectively created between first elastomeric gear 224 and second elastomeric gear 228 or, more specifically, teeth 226 and teeth 230. Hence, the rotated position of first elastomeric gear 224 is maintained until a rotational force is applied to rotate first elastomeric gear 224 with respect to second elastomeric gear 228.
While the use of elastomeric gears has been shown to be effective for providing up to approximately 360 degrees of hinging, machining elastomeric gears may be difficult. Elastomeric gears, e.g., rubber gears, may be difficult to accurately machine, as elastomeric materials are likely to deform while being machined. By way of example, deformation of elastomeric gears while teeth are being created along the circumference of the gears may cause the teeth to be inaccurately formed. As a result, when two elastomeric gears with defective teeth engage each other, they may not be able to accurately maintain a rotated position. Further, accurately machine teeth on deformable gears may be expensive.
Therefore, what is desired is a readily manufacturable hinge apparatus which allows for a wide range of rotation. Specifically, what is desired is an efficiently manufactured hinge apparatus that is suitable for use in a portable computing device and provides for a full, ie., up to approximately 360 degrees, range of rotation.